Don’t believe everything you read.
At least, apparently, when it comes to marijuana research.
An article recently appeared on Salon titled Science: Regular Consumption of Marijuana Keeps You Thin, Fit, and Active.
The writer made that statement based on new research from Oregon Health and Science University (OHSU).
In the OHSU paper, the following statement appears:
“Heavy users of cannabis [defined as having used marijuana five or more times in the past 30 days] had a lower mean BMI [body mass index] compared to that of never users; with mean BMI being 26.7 kg/m in heavy users and 28.4 kg/m in never users.”
The conclusions about health and fitness drawn by the Salon article hinged largely on that sentence.
“I want to reiterate that our study was not designed to examine the independent association between cannabis and BMI,” Carrie M. Nielson, an associate professor of epidemiology at OHSU and the lead author of the study, told Healthline.
“The Salon author took our result on BMI out of context,” she added.
What researchers were focusing on
Nielson and her team wanted to determine if there was any association between cannabis use and bone mineral density (BMD).
Bones contain cannabinoid receptors, which are responsible for numerous functions in the body, including potentially affecting BMD.
These receptors can be activated by cannabinoids, a class of chemical that is found in marijuana. The cannabinoid tetrahydrocannabinol (THC) is the primary psychoactive compound in marijuana.
In this study researchers did not observe an association between marijuana use and BMD.
As for conclusions about BMI drawn by the media, Nielson said there are other possible explanations.
The characteristics of marijuana users
BMI for the nearly 5,000 individuals in the study was just one of many recorded characteristics.
Others included age, race, daily alcohol consumption, tobacco usage, and illegal drug usage.
Heavy cannabis users had lower mean BMI than people who never used the drug, but the story doesn’t stop there.
Researchers stated that, compared with “never users,” heavy cannabis users were also heavier drinkers. They averaged 4.4 drinks per day, while the non-marijuana users averaged 1.9 drinks per day.
Marijuana users were also three times more likely to have smoked tobacco.
They also were significantly more likely to have used illegal drugs. Roughly 53 percent compared with just 2 percent of “never users.”
This finding was not included in the Salon article.
These statistics, though, aren’t a distraction from the argument that heavy cannabis users appear to have lower average BMI, but as an alternate explanation.
“The heavy users of cannabis in our study were also younger and had a very high prevalence of other illegal drug use. This is very likely to explain much of the apparent cannabis-BMI association,” explained Nielson.
Although Nielson’s findings on BMI were incidental, there is some prior research into the relationship between marijuana use and BMI.
A 2016 study concluded that daily marijuana users (both male and female) had lower BMI than nonusers.
However, according to other studies there needs to be more research on this relationship before a meaningful conclusion can be made.
Marijuana research remains a tricky subject because, despite legalization in numerous states, it remains a Schedule 1 drug.
The Drug Enforcement Agency (DEA) defines Schedule 1 drugs as having a high potential for abuse and no accepted medical uses.
This classification makes it more expensive and harder for researchers to access.
Nielson explained that as states continue to legalize marijuana and more people report using the drug — 60 percent of the population reported having used marijuana, according to the OHSU study — there is a greater need for more information about marijuana.
“Our conclusion was that there haven’t been a lot of well-done studies looking at any of these health aspects, either bone density, or obesity, or physical activity,” said Nielson, “but there is such a great proportion of people using it that we need better population based studies.”